Top plate for molds



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4TOP PLAT FOR MOLDS Filed oct. 2a, 1941 s sheets-sheet 1 k A l Y .A

n www y, 1 A TTo NEY W. lJ. CLAYTON El' AL Oct., l0, 1944c TOP PLATE FOR MOLDS Filed Oct. 28, 1941 5 Sheets-Sheet 2 INVENTORS WMZ/,4M d. 62A] YT/V (MH/v F w. J. CLAYTON z-:TAL 2,360,201

TOP PLATVE FOR MOLDS Filed Oct. 28, 1941 s sheets-sheet :s

INVETORS #wa/4M a. Myra/v 'Some of the most important Patentedoct. 10, i944 william J. clama and .mm r. schon, Mish- A awaka, Ind., assignors to United States Rubber Company, New York, N. Y., a corporation of New Jersey Application 'oculta 23,1941, serai No. 416,792

(cl. 1li-39)' 1 Claim.

invention relates'to the fabrication of shaped heat-treated articles, especially to the manufacture of such articles by setting foamable material into solid shapes, and' is oi particular use when employed in the fabrication of latex roam into' vulcanized sponge rubber cushions `forV automobiles, or into vulcanized sponge rubber .mattresses valthough the invention may be utilized in any iield for which it is adapted by the nature of our improvements. For a long time it has been'recognized that none ofthe present formulae for latex foamsponge can be used to produce in an open mold light density sponge which has a low and uniform vertical shrinkage.. In order to overcome this dliliculty it is well understood that some-form of a top plate must be used..

Other workers in this fleld have found thatsolid plates, cr plates with holes, cored plates,

and wire screens, could be used as top plates for latex foam molds. Each of these types 'or top plates can be used to produce sponge units which are satisfactory in general, but each such -form oi' ,top plate has one or more` disadvantages. of these expedients are listed below.

'A. Solid plateau-The bottoms-of the sponge l units which are produced in a mold with a solid top plate, are found to be covered with small cavities caused by entrapment of air. V(In most cases sponge units are molded in inverted molds, and therefore the plate covers what is to b'ecome the bottom side of the unit.)

' B. Solid .plates with hoZes.-The aforesaid cavities are reduced but not eliminated by using top plates which contain a large number ot vent holes.

C. Corellil platea-cored plates can be used to prevent excess vertical ridges but the stock produced is a cored stock rather than a solid mateadvantage in theiruse.

object of the invention to provide a oraminous top-plate structural element for such molds in which the openings are oi' suitable dimensions to permit the foam to rise into a multiplicity of the openings so that the top-plate will support the foam so engaged preparatory to vulcanization, but when vulcanized the resulting sponge rubber article and the foraminous top-plate may be neatly separated by a conventional stripping opasv sus

' pulled loose therefrom.

eration. The construction is preferably such that the top plate will aiord maximum support for the weight of the sponge mass without causing the sponge massto tear where the top plate is Other features and objects of the present invention will appear as progress is made in the description of the accompanying drawings, illustrative of a now preferred form of structure in the. making of which the ypresent invention has been carried into eiect.

In the accompanying drawings-like characters of reference have been applied to similar parts throughout the various gures which make up the drawings, in which:

Fig. 1 is a view in longitudinal sectional elevation of a molding apparatus in the construction of which the present invention has been embodied; Y

Fig. 2 is a view taken on tlie line 2-2 of Fig. l in vertical section;

. Fig. 3 is a plan view of the apparatus shown in V `trating the manner in which the latex foam Accordingly, an object of the present invention is to provide top plates for loam sponge molds which shall be free from the disadvantages' and inconveniences encounteredin the us'e of which will not only increase the convenience of fabrication of such foamsponge articles, but

will result in an increasedand more economical production of a more satisiactory'product.

under treatment reacts under application of the top plate constituting the present invention;

Fig. 6 is a fragmentary detail view in vertical sectional elevation of one of the elements of the perforated top plate illustrated in Fig. 5 and in Fig. l; and

Fig. 'l is a fragmentary detail view, Vtaken in .front elevation, of a part of ascraper used in forming a crowned surface'upon the latex'foam preparatory toits vulcanlzation in the apparatus of Fig. 1. A

Referring now to the drawings, Ill designates generally a vulcanizlng unit in whichja mold frame H is made to receive afsuitable quantity of latex foam which is the material that in this :Ancillary to the above general object, it is'an 55 instance is to be treated. The mold frame comprises uprightwalls I2, bolted at I3 to a mold bottom plate I4 which is in turn supported by 'a metal plate I5 mounted upon a foundation I6 which may be made of concrete or cement, or other suitable material.

The foam I1 to be treated occupies the central cavity enclosed by the walls I2 and'bottom I4 of the mold, and provision is made for a suitable source of heat, such as the pipes I8 leading from a steam line I9 having a control valve 20.

For the purpose of introducing water, a supply pipe 2| is illustrated, having a control valve 22 and preferably leading to a spray .pipe 23 which may desirably be disposed in a recess 24 formed in the concrete base I6, this -recess being adapted to serve also as a sump from which liquid may be withdrawn through a drain pipe 25, controlled Y by a valve 26. An oven 2l of conventional or other suitable form and material, such as sheet metal, may be the upstanding foam, the latter preferably occupies substantially the position indicated by full lines in Fig. 5, and after its heat-treatment, such as Vulcanization, the foam may rise to approximately the height 4I indicated by dotted lines in Fig. 5, taking the form of a multiplicity of small cushion-like elements which present somewhat the appearance of square loaves.

After vulcanization in the conventional or other suitable manner, the grid may be lifted from the contiguous surface made up of these sponge rubber subdivisions of the main surface, which are found to clear themselves neatly from the circumjacent partitions 36, leaving the latter with few accretions, which can be readily washed,

brushed or scraped ofi preparatory to the next use of the grid.

From the foregoing disclosure, it is clear that we have provided a structural top-plate element raised and lowered by the Kbridle 28 and cable 29,

and when in use is shown as resting at 30 upon a steel plate 3| supported upon the base I6.

In pursuance of the invention, provision is made of a top plate 33, taking the form of a.

foraxninous structural element adapted to be' disv posed above the foam-filled cavity I'I, resting upon the upper edges 32 of the side walls I2.

This element may be of any construction adapted to afford multiplicity of deep openings, as 34, into which the foam I 'I may extend in the form of upright projections 35, (see Fig. 5) separated from each other by' grooves or slots which are made by the vertical'partitions 36 that define the openings 34. These openings are of uniform cross section throughout their height. This pre-v vents clogging of the grill and facilitates strip ping of the grill without tearing the molded material.

In the instance illustrated rectangular aper-` tures 34 are constituted by the upright metal partition members 36 which are notched at 31 and interfit to form a grid, being fastened to a peripheral metal frame 38 by suitable fittings such as the hook-bolts 39 illustrated in Fig. 5.

In the operation of the mold,'the space II is filled with foam to a height which may desirably of a foraminous character which is constructed and arranged to carry into effect the stated objects of the instant invention, particularly in the important respects that the walls of the openings 34 are adapted to support the foam, which rises to a suitable distance into the openings 34 but does not penetrate far enough to run together above the top of the plate, so that there is no tendencyfor the resulting sponge rubber unit.

to be torn when the plate is stripped; and the foraminous grate is further serviceable in the important respect that it does not clog readily,

and may be easily kept clean.

Having thusdescribed our invention, what we claim and desire to protect by Letters Patentis: In a mold of the class intended for use in the fabrication of shaped articles from latex foam and like moldable material adapted to be set in solid form, and in combination with a bottom wall andl so as to support the weight of the foam mass and permit said solid foam to be stripped in substantially intact condition from the grid.

WILLIAM J. CLAYTON. JOHN F. SCHOTT. 

